Patent GB-190514407-A (GB)
Title: Improvements in Air Brakes.
Filed: 1905-07-12
Granted: 1906-03-15
Abstract: 14,407. Westinghouse Brake Co., [Westinghouse Air Brake Co.]. July 12. Brakes.-Automatic airpressure brake apparatus, of which a complete set is fitted to each vehicle, is adapted to be operated from any one of the vehicles when several of them are formed into a train. A special feed valve is fitted to each driver's valve and arranged to be controlled by auxiliaryreservoir pressure when the driver's valve is in "lap" position in the train, and to supply air from its main reservoir to both the train-pipe and its auxiliary reservoir at relative rates which can be varied, other objects being a rapid recharging of the auxiliary reservoirs and a graduated release of the brakes. Each vehicle carries a main reservoir 1, motor-driven air-pump 2, pump governor 3, main-reservoir pipe 4 leading to the driver's valves 5, feed valves 10, train-pipe 6, triple valve 7, auxiliary reservoir 8, and brake cylinder 9. The driver's valve, as shown in Fig. 2, is of the rotary type, and provides a permanent connexion between the main reservoir and the chamber of the slide valve 23 through the passage 4, above the rotary disk 18, and through the passage 14. The disk 18 has a port 39, Fig. 4, and cavities 16, 37 with an extension 38. When the driver's valve is in the "running" position shown, train-pipe pressure has access to a diaphragm 33 in the feed valve through ports and passages 13, 17, 16, 15. When this pressure falls below the normal, the diaphragm is raised by a spring 36 and opens a valve 35, allowing the reservoir air which has leaked round a piston 20 to escape from the chamber 21. This causes the piston 20 to move to the right and open a port 25, so that mainreservoir pressure can pass to the train-pipe through passages 28, 26. To enable this same valve 10 to control the air passage from the main reservoir to the train-pipe when its driver's valve is "lapped" and the brakes are being operated from another driver's valve in the train, it is formed with additional ports 24, 27, connected to the triple valve through a pipe 11. In this "lapped" position of the driver's valve, the passage 15 to the train-pipe is obturated, and the diaphragm 33 is governed by auxiliary-reservoir pressure acting through ports and passages 55, 51, 11 when the triple valve is in the release position shown. For service applications, the driver's valve which is operating the brakes throughout the train is moved to close its port 15 and vent the trainpipe to atmosphere through cavity 37 and its extension 38. The consequent movement of the triple-valve piston 42 on. each vehicle first moves the graduating-valve 45, disconnecting the brake cylinder from the exhaust and closing the port 55 leading to the feed valve, and then draws the main slide valve to the position in which the auxiliary reservoir and brake cylinder are connected through ports 46, 47, the feed valve meanwhile remaining closed. When the operating driver's valve is turned to release position, to connect the train-pipe to its main reservoir through port 39, it may also be arranged to connect ports 17, 15 as in the "running" position, and thus connect the diaphragm 33 to the train-pipe, whereby the valve 35 will be opened and the slide valve 23 moved to open the ports 25, 27. Air will then flow from the main reservoir to the train-pipe both through the passages 25, 26 and the passages 24, 27, 15, and to the auxiliary reservoir through passages 24, 27, 11, 51, 55. When the triple valves on the vehicles with the "lapped" driver's valves have moved sufficiently to connect their auxiliary reservoirs with the diaphragms 33, the feed valves will be operated to supply air to the train-pipe through ports 25 and to the respective auxiliary reservoirs through ports 24. To cause the auxiliary-reservoir pressure to increase as rapidly as that of the train-pipe, a feed port 56 may be so arranged as to be open in the release position of the triple valve, and by connecting this port to the emergency valve chamber 60 of the triple valve, the usual check valve 61 will serve to prevent back flow from the auxiliary reservoir. Since each triple valve piston, as soon as it moves to "service" position, closes the port 55, the pressure will readily equalize around the pistons 20 and the feed valves will then close. Thus the pressures in the auxiliary reservoirs and the trainpipe will remain practically equal, so that the brakes can be promptly applied while the system is recharging. In the " emergency position of the driver's valve, the train-pipe is vented through cavity 37, and the usual emergency valve 59 of the triple valve is opened. To permit of a partial reduction of brake-cylinder pressure, or a gradual release of the brakes, a restricted port may be arranged in the cock 30 between the passages 25, 26. The operating driver's valve is turned to "release" or " running position for a moment, whereby its feed valve is opened and train-pipe pressure raised sufficiently to move the triple valves to "release" position. This causes air to be supplied from each main reservoir to the train-pipe through the restricted port, and to the auxiliary reservoir through a larger port, so that the triple valve pistons are soon returned to their " application " positions. The graduating release may be cut out by turning the cock 30, whereby more air can be arranged to pass to the train-pipe than to the auxiliary reservoir, or the cock 30 and the ports 24, 27 may be dispensed with, the rapid recharging of the auxiliary reservoir being effected through the port 56 as explained above.